SAN FRANCISCO–Scientists have discovered a genetic mutation that is associated with a type of familial early-onset puberty, according to a new clinical study. The results were presented Monday at The Endocrine Society’s 95th Annual Meeting in San Francisco.

“Using modern genetic techniques, we found a new gene that when mutated leads to early puberty,” said Andrew Dauber, MD, MSc, instructor in pediatrics at Boston Children’s Hospital in Massachusetts, who worked closely on this project with Ana Paula Abreu, MD, a research fellow at Brigham and Women’s Hospital in Boston. “This gene has never been connected to the biology of puberty in the past, and little is known about its function.”

Precocious puberty is the development of secondary sexual characteristics and other related changes before the age of eight years in girls and nine years in boys. The disorder affects more girls than boys, and is becoming more common, although the reasons for this are unclear. What is clear is that many factors affect the timing of puberty, including genetics, environment, nutrition and obesity.

Since young children are not emotionally ready for these adult changes in their bodies, precocious puberty can cause a great deal of anxiety related to the feeling of being different, as well as to the physical development itself. In addition, children may bully others who are seen as different, contributing to the bullied child’s emotional distress.

In terms of physical development, precocious puberty can result in shorter stature in adults because the bones stop growing prematurely. Among girls, early development can increase the risk of breast cancer.

For these reasons, medical researchers are seeking ways to identify potentially modifiable risk factors for precocious puberty. Since more than one member of the same family often is affected, researchers are trying to identify the genes that play a role in early sexual development.

Dauber – along with his collaborators led by Ursula Kaiser, MD, at Brigham and Women’s Hospital and Ana Claudia Latronico, MD, PhD, at the University of Sao Paulo – found mutations in a single gene in one-third of families with histories of precocious puberty that occurred between the ages of five and eight years. Symptoms included breast development, pubic hair growth, greater early height and bone age, and increased hormonal concentrations that are associated with the onset of puberty. Among the girls in the participating families, breast development occurred, on average, when they were six years old.

To identify the gene, the investigators examined genetic information from 40 individual family members from 15 families participating in the study. They used an advanced genetic test, called whole exome sequencing, which analyzes the protein-coding component of the genes, to identify the mutation. The whole exome sequencing was performed at the Broad Institute.

“Our research is going to open the door for an entirely new understanding of what controls the timing of puberty,” Dauber said. “It also will allow doctors to diagnose the cause of precocious puberty in a subset of patients.”

Boston Children’s Hospital, the National Institutes of Health, and research-funding agencies in Brazil supported the study.

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